It is well known to use metal oxides, particularly iron oxide (FexOy) in a reactor bed to remove contaminants, typically sulfur compounds, especially hydrogen sulfide (H2S), from fluids, typically gas streams. Sulfur compounds are removed from fluids because they are known contaminants, which potentially make gas streams or other fluids unsalable. Gas that contains too much sulfur is known as sour gas. As such, in the gas industry, as well as related industries, it is considered necessary to remove sulfur compounds from fluids, including gas. Note that these fluids are typically devoid of oxygen (it is known that oxygen can increase reactivity between a metal oxide composition and contaminants). For this reason, there is a need for products that remove sulfur compounds from fluids efficiently and cost effectively. It is further desired to have a method or composition that does not require the inclusion of activating agents, such as oxygen.
Sulfur removal on a level that treats up to millions of cubic feet of gas per day or on an industrial scale, typically requires the use of large reactor beds filled with a desulfurizing product. In one embodiment, such desulfurizing products comprise iron oxide on a carrier such as montmorillonite or wood chips. In order to have a sufficient bed life, large amounts of desulfurizing product are used. One way to increase the amount of sulfur held in a reactor vessel is to use another desulfurizing product embodiment in which the metal oxide is pelletized or compressed thereby increasing the amount of metal oxide per unit of desulfurizing product volume. By way of comparison, a carrier-type desulfurizing product typically comprises approximately 20% by weight metal oxide and 80% by weight of carrier whereas a pelletized-type desulfurizing product typically comprises from about 80% to about 99% metal oxide and about 1% to about 20% by weight binder.
Using such conventional desulfurizing products to remove sulfur contaminants from a fluid stream (e.g., natural gas, flu gas, and/or the like) results in the chemical reaction of the iron oxide to iron sulfide until such time as the desulfurizing product in a reactor vessel, wherein the contact between the desulfurizing product and the fluid stream previously occurred, is effectively “spent”. The spent desulfurizing product is then removed from the reaction vessel but doing so is typically difficult because during use the desulfurizing product particles tend to agglomerate. In fact, it is typical for essentially all of the spent desulfurizing product in a reaction vessel to have become a unified mass. Often, removal of the spent desulfurizing product from a reaction vessel requires physical force such as by jackhammer, and/or by contacting the spent composition with high pressure water jets having a pressure on the order of 3,000 to 10,000 psi. Such processes, typically result in undesirably long downtimes and costs in terms of man-hours and equipment.
Thus, a need still exists for a desulfurizing product that tends not to agglomerate during use such that when spent its removal from a reaction vessel does not require such physical force.